What to do when you put the wrong fuel in your car

Petrol Station

If you’ve just used the wrong fuel, don’t switch on the engine or put the key in the ignition, this could cause further damage.

We all make mistakes from time to time and you’re not alone in your error so don’t lament, it’s a common mistake. All it takes is a small loss in focus, perhaps you’re tired or your mind is occupied elsewhere and before you’ve realised it, your vehicle is guzzling the wrong fuel.

But don’t fret, if this has happened to you, read our guide on how to get sorted.

What happens if you put diesel in a petrol car?

This one’s harder to do since diesel pump nozzles are typically larger than petrol fuel necks. If you have done this then diesel in petrol engine is not as bad as petrol in a design engine.

Diesel needs to be compressed before it’ll ignite so you probably won’t even be able to start the engine and do any serious damage.

What happens when you put petrol in a diesel engine?

Petrol is a lubrication oil as well as a fuel to power the car, ensuring components are running correctly. Petrol on the other hand acts as a solvent when mixed with diesel which has the opposite effect.

If you were lucky enough to spot your error before turning on the vehicle then you’ll need to get it drained and the damage won’t be as severe, this can be done by calling your breakdown provider who will be able to assist further.

What if I turned the ignition on?

If you started the engine then you’ll not only need to get the vehicle drained, but have the fuel pipes flushed too. This can be expensive to repair depending on the severity of the contamination.

What to do if you’ve put the wrong fuel in the car

A step-by-step plan of action if you’ve accidentally used the wrong fuel to fill up.

  • Remove keys from the ignition if you haven’t already.
  • Tell the petrol station the situation – it’ll be a familiar scenario for them, and they should be able to provide assistance.
  • Push the car to a safe location.
  • Call your breakdown cover – this often comes as standard with your annual car insurance policy and they have dedicated misfuelling teams who will be able to assist you.

How to prevent filling up with the wrong fuel

Putting the right precautions in place could help you save a fortune in damage repairs. Since misfuelling is such a frequent scenario, there’s a whole range of tools to help you avoid the problem.

For instance, a device with light activated voice memos you stick onto your vehicle can give you an audible reminder to fill up your car with the correct fuel once you open the fuel cap. Another handy little device is a misfuelling prevention cap, designed to prevent the insertion of a smaller diameter nuzzle, this is diesel only since the problem would not typically occur with petrol vehicles. Another option is stickers, which can be applied to the filler cap area to give you a visual reminder whenever it’s time to fuel.

For more hints and tips on all things motor, visit the driving section of our blog.



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